Electric resistance heater with spaced insulators and an inter-connectable flexible metallic base strip

ABSTRACT

An electric heater comprising a flexible base strip, insulators spaced apart along and having flats seated on one side of the base strip, each insulator being provided intermediate its ends with an aperture generally perpendicular to and having an end adjacent the base strip, each of the insulators being provided between the aperture and the respective ends of the insulator with shoulders which extend to the aperture and which face away from the base strip, the base strip having two integral prongs within the aperture of each insulator and respectively bent toward opposite ends of such insulator over the shoulders thereof to secure same to the base strip, and electrical resistance elements threaded through openings in the insulators.

United States Patent [191 Potter 51 Feb. 27, 1973 [76] Inventor: Paul H. Potter, 544 Fantasy Street,

Palmdale, Calif. 93550 [22] Filed: July 7, 1971 21 Appl. No.: 160,467

[52] U.S. Cl. ..219/550, 174/138 .1, 219/310,

219/536, 338/213, 339/220 R [51] Int. Cl. ..H05b 3/02 [58] Field of Search ..219/532, 536, -537,

219/550, 552-553, 306, 310, 316,338/213; 174/199 R, 138 J; 339/125, 220 R, 220 C,

1,997,146 4/1935 Hynes "219/534 3,136,885 6/1964 Hynes 174/99 R X 3,286,079 11/1966 Hynes et a1 ..2l9/3 10 3,302,003 1/1967 Kinney ..2l9/550 3,519,795 7/1970 Kinney ..219/310 3,601,752 8/1971 Panza ..339/220 R X Primary Examiner-Volodymyr Y. Mayewsky Attarney-Harris, Kern, Wallen & Tinsley [5 7] ABSTRACT An electric heater comprising a flexible base strip, insulators spaced apart along and having flats seated on one side of the base strip, each insulator being provided intermediate its ends with an aperture generally perpendicular to and having an end adjacent the base strip, each of the insulators being provided between the aperture and the respective ends of the insulator with shoulders which extend to the aperture and which face away from the base strip, the base strip having two integral prongs within the aperture of each insulator and respectively bent toward opposite ends of such insulator over the shoulders thereof to secure same to the-base strip, and electrical resistance elements threaded through openings in the insulators.

2 Claims, 6 Drawing Figures 1 ELECTRIC RESISTANCE HEATER WITII SPACED INSULATORS AND AN INTER-CONNECTABLE FLEXIBLE METALLIC BASE STRIP BACKGROUND OF INVENTION 3 The present invention relates in general to electric heaters.

. The invention contemplates an electric heater of the type which includes a series of insulators having laterally spaced, electrical resistance elements threaded through openings therein. More particularly, the invention contemplates a heater of this character wherein the insulators are spaced apart along and secured to a flexible base strip which is preferably metallic.

Prior U. S. Pat. relating to the subject matter of the present invention include: Apfel, No. 1,699,323, Jan. 15, 1929;1-lynes, No. 1,997,146, Apr. 9, 1935; I-Iynes, No. 2,750,487, June 12, 1956; Kinney, No. 2,888,546, May 26, 1959; Kinney, No. 3,302,003, Jan. 31, 1967; and Kinney, No. 3,519,795, July 7, 1970.

SUMMARY AND OBJECTS OF INVENTION The primary object of the present invention isto provide an improved means for attaching'the insulators to the base strip in an electric heater of the character hereinbefore outlined. More particularly, an important object is to provide an attachment means which secures the insulators to the base strip in a manner which is very simple, but nevertheless positive and reliable.

An important object of the invention is to provide each insulator intermediate its ends with an aperture generallyperpendicular to and having an endadjacent the base strip, and to provide each insulator between the aperture and the respective ends of the insulator with shoulders which extend to the aperture and which face away froma flat seated against the base strip. A relatedobjectis to provide thejbase strip with two integral prongs within the aperture of each insulator and respectivelybent toward opposite ends of suchinsula- I tor over the respective shoulders mentioned. Another related object is to provide an insulator wherein the shoulders mentioned formwalls of openings extending to the respective ends of the insulator for bending access to the attachment prongs.

With the foregoing construction, the insulators are easily and positively secured to the base strip, which is an important feature. g

The foregoing objects, advantages, features and results of the present invention, together with various other objects, advantages, features and results thereof which will be evident to those skilled in the electric heater art in the light of this disclosure, may be achieved with the exemplary embodiment of the invention illustrated in the accompanying drawing and described in detail hereinafter.

DESCRIPTION OF DRAWING In the drawing: FIG. 1 is a side elevational view of an electric heater which embodies the invention;

FIG. 2 is an enlarged, fragmentary bottom plan view thereof;

FIG. 3 is a transverse sectional view taken as indicated by the arrowed line 3-3 of FIG. 4;

FIG. 4 is a longitudinal sectional view taken as indicated by the arrowed line 4-4 of FIG. 3;

FIG. 5 is a fragmentary perspective view of a flexible base strip showing insulator securing prongs before bending; and

FIG. 6 is a view similar to FIG. 5, but showing the prongs after bending, with the corresponding insulator removed for clarity.

DESCRIPTION OF EXEMPLARY EMBODIMENT OF INVENTION The electric heater of the invention is designated generally by the numeral 10 and includes a flexible, preferably metallic, base strip 12 carrying insulators 14 in longitudinally spaced relation. The insulators 14 have flats I6 seated against one side of the base strip 12 and are secured to the base strip in a manner to be described hereinafter. The insulators 14, which have convex ends 18, are provided therethrough with openings 20 for electrical resistance elements 22. Certain of these elementsare secured attheir ends to bars 24 inserted into slots 26 coaxial and coextensive with the openings 20. The latter preferably have beveled ends 28 to facilitate insertion of the resistance elements 22.

Each insulator 14 is provided intermediate its ends with an aperture, preferably a slot 30, generally perpendicular to and having an end adjacent the base strip 12. The plane of the slot 30 substantially coincides with the transverse midplane of the insulator.

Each of the insulators 14 is provided internally thereof with two shoulders 32 and 34 which are parallel to the corresponding flat 16 and which extend from the respective ends 18 of the insulator to the slot 30. The shoulders 32 and 434 respectively form walls of openings 36 and 38 extending from the respective ends of the-insulator to the slot 30.

Each insulator 14 is secured to the base strip 12 by two oppositely struck, integral prongs 40 and 42 in edge-to-edge relation, as best shown in FIG. 5. The

prong 40 is bent over and engages the shoulder 32 and the prong 42 is bent over and engages the shoulder 34. The thickness of the prongs 40 and 42 is slightly less than the thickness of the slot 30, and the total of the widths of the prongs is slightly less than the width of the slot 30. The prongs 40 and 42 may be bent over the respective shoulders 32 and 34 by suitable tools inserted through the openings 36 and 38.

With the foregoing construction, each insulator 14 is positively and reliably secured to the base strip 12 in a very simple and inexpensive manner, which are important features of the invention.

It will be noted that the shoulders 32 and 34 of each insulator 14 are spaced difierent distances from the corresponding flat 16. With this construction, the slot 30 may be formed with simpler dies.

Although an exemplary embodiment has been disclosed for illustrative purposes, it' will be understood that various minor changes, modifications and substitutions may be incorporated in this embodiment without departing from the spirit of the invention as defined by the claims which follow.

I claim as my invention:

1. In an electricheater, the combination of:

a. a flexible metallic base strip;

b. insulators spaced apart along and having flats said insulator;

seated on one side of said base strip; e. said base strip having two integral prongs within c. each of said insulators being provided intersaid aperture of each of said insulators and respecmediate its ends with an aperture generally pertively bent toward opposite ends of said insulator pendicular to and having an nd adj nt id b 5 over said shoulders thereof and extending into said strip; openings; and

d. each of said insulator b i id d tween f. electrical resistance elements paralleling said base said apert d th respective d of id i strip and threaded through holes in said insulators. lator with shoulders which extend to said aperture An electric heat" as defined in claim 1 wherein and which f away f said base strip said said shoulders of each of said insulators are spaced difshoulders of each of said insulators forming walls ferem distances fmm said base pof openings extending to the respective ends of 

1. In an electric heater, the combination of: a. a flexible metallic base strip; b. insulators spaced apart along and having flats seated on one side of said base strip; c. each of said insulators being provided intermediate its ends with an aperture generally perpendicular to and having an end adjacent said base strip; d. each of said insulators being provided between said aperture and the respective ends of said insulator with shoulders which extend to said aperture and which face away from said base strip, said shoulders of each of said insulators forming walls of openings extending to the respective ends of said insulator; e. said base strip having two integral prongs within said aperture of each of said insulators and respectively bent toward opposite ends of said insulator over said shoulders thereof and extending into said openings; and f. electrical resistance elements paralleling said base strip and threaded through holes in said insulators.
 2. An electric heater as defined in claim 1 wherein said shoulders of each of said insulators are spaced different distances from said base strip. 